Thin film light emitting diode

ABSTRACT

Light emitting LEDs devices comprised of LED chips that emit light at a first wavelength, and a thin film layer over the LED chip that changes the color of the emitted light. For example, a blue LED chip can be used to produce white light. The thin film layer beneficially consists of a florescent material, such as a phosphor, and/or includes tin. The thin film layer is beneficially deposited using chemical vapor deposition.

This application is a continuation of prior U.S. patent application Ser.No. 10/975,095 filed Oct. 28, 2004, which is a divisional of U.S. patentapplication Ser. No. 10/179,010 filed Jun. 26, 2002, now U.S. Pat. No.6,841,802, each of which is incorporated herein by reference in itsentirety

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to diodes (LEDs), and more particularly,present invention relates to light emitting diodes LEDs.

2. Discussion of the Related Art

Light emitting diodes LEDs are well-known semiconductor devices thatconvert electrical current into light. An LED produces light by excitingelectrons across the band gap between a conduction band and a valenceband of a semiconductor active (light-emitting) layer. The electrontransition generates light at a wavelength (color) that depends on theband gap. Thus, the color of the light (wavelength) emitted by an LEDdepends on the semiconductor material(s) of the active layer.

LEDs are widely available in a range of colors, for example, red, green,blue, yellow, and orange. However, conventional LEDs are relativelymonochromatic light sources. Unfortunately, some applications requirewhite light, which includes all primary colors. For example, laptopcomputers often require white-light backlights. Usually, white light issupplied either by incandescent bulbs or by fluorescent lamps. Althoughinexpensive, incandescent bulbs have fairly short lifetimes and lowluminous efficiency. While more efficient, fluorescent lamps also tendto have limited lifetimes. Furthermore, fluorescent lamps requirerelatively large, heavy and expensive support devices, such as voltagestabilizers.

A white LED source could be made by fabricating closely spaced (orotherwise light-mixed) red, green, and blue LEDs that emit light inproper proportions. However, blue LEDs have been relatively difficult tofabricate, primarily because of difficulties in fabricating high qualitycrystals having a suitable band gap. Despite these difficulties, blueGaN-based LEDs have recently become commercially available. This hasenabled white LEDs to actually be fabricated by mixing green, red andblue light together.

While successful in producing white light, three-component (green, redand blue) LEDs have problems. For example, three-component LEDs will usesignificantly more power than a single component LED. Additionally,three-component LEDs require careful balancing of optical outputs toachieve high quality white light, a balance that is difficult tomaintain over time and temperature, and that requires careful andexpensive fabrication. The necessity of optical balancing combined witha relatively complicated drive circuitry means that three-component LEDsare, in practice, difficult and expensive to fabricate.

Because of the forgoing problems with three-component LEDs it is wouldbe advantageous to produce white light using only a single-element LED.Such single element white LEDs are known. For example, FIG. 1illustrates a prior art single-element, white LED 12. The LED 12incorporates an yttrium-aluminum garnet (YAG) phosphor. Essentially, thephosphor layer produces white light from blue light. As shown, thesingle element white LED 12 is comprised of a blue LED chip 14 that islocated on a base 15, which is inside an organic YAG phosphor 16. TheYAG phosphor 16 is embedded in a dome-shaped package 17 having ahemispherical top 18. The package 17 protects the resulting LED fromdamage caused by static electricity, moisture, and other environmentalinfluences. Extending from the package 17 are two leads 20 and 22.Bonding wires 24 and 26 connect the anode and cathode of the LED chip 14to the leads 20 and 22.

Still referring to FIG. 1, when electric power is applied to the LEDchip 14 via the leads 20 and 22 and the bonding wires 24 and 26, the LEDchip 14 emits blue light. A part of the blue light passes through theYAG phosphor 16, while another part is absorbed by the YAG phosphor 16.The result is white light from the package 17.

Thus, a key to making white LEDs using the method illustrated in FIG. 1is suitable blue LEDs. A beneficial approach to fabricating such blueLEDs is to incorporate active layers comprised of Gallium-Nitride (GaN)and Indium to produce InGaN/GaN semiconductor layers. In fact, theenergy efficiency of GaN-based white LEDs has surpassed that ofincandescent lamps, and is now comparable with that of fluorescentlamps.

Despite their numerous advantages, white LEDs similar to the one shownin FIG. 1 have problems. One set of problems relates to degradation ofthe bonding wires 24 and 26, the LED chip 14, and the leads 20 and 22due to direct contact and subsequent chemical reaction with the YAGphosphor 16. Additionally, the YAG phosphor 16 can be degraded by suchchemical reactions.

Another problem with white LEDs similar to the one shown in FIG. 1 isthat the hemispherical top 18 of the package 17 results in a “ringpattern” in the emitted light. Thus, the emitted light has poorluminance uniformity. The hemispherical top 18 also makes it difficultto reliably coat phosphors inside the package if such coating isrequired.

Another problem with white LEDs similar to the one shown in FIG. 1 isthat the actual production of white light does not come from thelight-producing LED chip 14, which emits only blue light, but fromphosphor 16 within the package 17. Thus, the package not only providesprotection, it is a functional requirement. Thus, the foregoingtechnique is not well suited for use with surface mount packaging.

U.S. Pat. No. 6,337,536, by inventors Matsubara et al., which issued onJan. 8, 2002, and which is entitled, “White color light emitting diodeand neutral color light emitting diode,” discloses a white lightemitting source that uses an n-type ZnSe single crystal substrate. Thesubstrate is doped with I, Cl, Br, Al, Ga, or In emission centers, andincludes an epitaxial film active layer structure of ZnSe, ZnCdSe orZnSeTe. The active layer emits blue or blue-green light. The emissioncenters convert the blue or blue-green light to yellow or orange. Theblue or blue-green light and the yellow or orange light synthesize whitelight or a neutral color light between red and blue.

While the techniques taught in U.S. Pat. No. 6,337,536 are generallysuccessful, they have problems. For example, U.S. Pat. No. 6,337,536teaches a thick substrate. Therefore, the light intensity is heavilydependent on the thickness of the substrate. Furthermore, the materialsused in U.S. Pat. No. 6,337,536 may not be optimal in specificapplications.

Therefore, a new single-element, white LED would be beneficial.Particularly beneficial would be a single-element, white LED thatreduces or eliminates bonding wire, LED chip, connector lead, andphosphor degradation. Also beneficial would be a single-element, whiteLED that does not produce a ring pattern and that improves theuniformity of emitted light. Such a single-element, white LED wouldbeneficially be fabricated as an on-chip, single-element, white LED thatdoes not require a package for white light emissions. A method offabricating white light emitting diodes without coating phosphor insidepackages would be useful. Also beneficial would be a single-element,white LED with a light output that does not depend on the thickness of asubstrate. More generally, a method of fabricating light emitting diodesusing thin film fluorescent coatings would be beneficial.

BRIEF SUMMARY OF THE INVENTION

The following summary of the invention is provided to facilitate anunderstanding of some of the innovative features unique to the presentinvention, and is not intended to be a full description. A fullappreciation of the various aspects of the invention can be gained bytaking the entire specification, claims, drawings, and abstract as awhole.

The principles of the present invention provide for white LEDs and formethods of fabricating white LEDs. Embodiments of white LEDs that are inaccord with the principles of the present invention have reduced oreliminated bonding wire, LED chip, lead, and/or phosphor degradation.Such white LEDs can be fabricated on-chip, with improved lightuniformity, and in such a manner that the light output is not heavilydependent on the thickness of a substrate.

According to the broad principles of the present invention, an LEDelement that produces light at a first wavelength and having p and ncontacts is fabricated on a substrate. Then, a tinted thin film coversthe LED element. A passivation layer is located on the LED element, butin such a manner that the p and n contact pads are exposed. Electricalpower applied to the p and n contacts causes the LED element to emitlight at the first wavelength. The thin film converts light at the firstwavelength to at least a second wavelength.

According to the principles of the present invention a white LEDincludes a blue-LED element that includes p and n contact pads. A thinfilm material, such as a phosphor (like YAG) or a tin-containingcompound, covers the blue-LED element. Such thin film materials arebeneficially formed using metal organic chemical vapor deposition(MOCVD), atomic layer chemical vapor deposition (ALD), plasma enhancedMOCVD, plasma enhanced ALD, photo enhanced CVD, or other chemical vapordeposition methods.

A passivation layer, beneficially about a 1000 Å-thick SiO₂ orSi_(x)N_(y) layer, can be located on the blue-LED element, but in such amanner that the p and n contact pads are exposed. The passivation layercan be formed using PECVD, sputtering, electron beam evaporation, orcoating with a material, such as epoxy or flowable Si0₂. PECVD isparticularly beneficial in that it provides protected sidewalls.Spin-coating is a useful method of material coating. The passivationlayer can then be patterned to expose the p and n contact pads usingphotolithography and a suitable etchant (such a BOE, HF, and/orphoto-resist stripping).

Wire bonds connect to the p and n contact pads. A second passivationlayer can be formed over the p and n pads, over ends of the wire bonds,and over the first passivation layer. The result is an on-chip,single-element, white LED that is cap able of emitting white-lightwithout being encapsulated. Furthermore, an on-chip, single-element,white LED can be formed without a ring-patterned light. However, theresulting on-chip, single-element, white LED could be encapsulated in apackage (such as a lamp or surface mount package) as required.

According to the principles of the present invention, an LED includes anLED element that includes p and n contact pads and that emits light at afirst wavelength. A fluorescent thin film material (such as a phosphoror a tin-containing material) covers the LED element. Such thin filmmaterials are beneficially formed using metal organic chemical vapordeposition (MOCVD), atomic layer chemical vapor deposition (ALD), plasmaenhanced MOCVD, plasma enhanced ALD, photo enhanced CVD, or otherchemical vapor deposition methods. A passivation layer, beneficiallyabout a 1000 Å-thick SiO₂ or Si_(x)N_(y) layer, can be located on theLED element, but in such a manner that the p and n contact pads areexposed. The fluorescing material converts light emitted by the LEDelement into at least a second wavelength.

The novel features of the present invention will become apparent tothose of skill in the art upon examination of the following detaileddescription of the invention or can be learned by practice of thepresent invention. It should be understood, however, that the detaileddescription of the invention and the specific examples presented, whileindicating certain embodiments of the present invention, are providedfor illustration purposes only because various changes and modificationswithin the spirit and scope of the invention will become apparent tothose of skill in the art from the detailed description of the inventionand claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, in which like reference numerals refer toidentical or functionally-similar elements throughout the separate viewsand which are incorporated in and form part of the specification,further illustrate the present invention and, together with the detaileddescription of the invention, serve to explain the principles of thepresent invention.

FIG. 1 illustrates a prior art white LED;

FIG. 2 illustrates a prior art lateral topology blue LED;

FIG. 3 illustrates a prior art vertical topology blue LED;

FIG. 4 illustrates a vertical topology, blue LED after coating with apassivation material;

FIG. 5 illustrates the LED of FIG. 4 after patterning of the passivationmaterial;

FIG. 6 illustrates the LED of FIG. 5 after forming of a thin film;

FIG. 7 illustrates the LED of FIG. 6 after patterning of the thin filmand after bonding wires are connected;

FIG. 8 illustrates the LED of FIG. 7 after a second coating of apassivation material; and

FIG. 9 illustrates an alternative embodiment LED that is in accord withthe principles of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The following generally describes a process for fabricating on-chipwhite LEDs. While that description is an advantageous method offabricating white LEDs, the principles of the present invention are notlimited to that described method. Accordingly, the present invention isto be limited only by the claims that follow as understood andinterpreted according to United States Patent Laws.

Fabrication of a white light emitting diode that is in accord with theprinciples of the present invention begins with procurement of, such asby fabrication, a blue-LED chip having p and n contact pads. FIGS. 2 and3 illustrate suitable blue-LED chips. In particular, FIG. 2 illustratesa lateral topology blue-LED chip 30 that is fabricated on a sapphiresubstrate 32. An n-GaN buffer layer 34 is formed on the substrate 32. Arelatively thick n-GaN epitaxial layer 36 is then formed on the bufferlayer 34. An active layer 38 having multiple quantum wells ofaluminum-indium-gallium-nitride (AlInGaN) or of InGaN/GaN is then formedon the n-type GaN epitaxial layer 36. A p-GaN layer 40 is then formed onthe active layer 38. A transparent conductive layer 42 is then formed onthe p-GaN layer 40. The transparent conductive layer 42 may be made ofany suitable material, such as Ru/Au, Ni/Au or indium-tin-oxide (ITO). Ap-type electrode 44 is then formed on one side of the transparentconductive layer 42. Suitable p-type electrode materials include Ni/Au,Pd/Au, Pd/Ni and Pt. A p contact pad 46 is then formed on the p-typeelectrode 44. Beneficially, the p contact pad 46 is Au. The transparentconductive layer 42, the p-GaN layer 40, the active layer 38 and part ofthe n-GaN layer 36 are then etched to form a step. Because of thedifficulty of wet etching GaN, a dry etch is beneficially usually usedto form the step. The LED 30 is then completed by forming an n-electrodepad 48 (such as Cr or Au) and an n contact pad 50 (such as Au) on thestep.

FIG. 3 illustrates an alternative blue LED, specifically a verticaltopology GaN-based LED 54. An example of this alternative blue LEDstructure is disclosed in U.S. application Ser. No. 09/905,969 entitled“DIODE HAVING HIGH BRIGHTNESS AND METHOD THEREOF” filed on Jul. 17,2001, and U.S. application Ser. No. 09/983,994 entitled “DIODE HAVINGVERTICAL STRUCTURE AND METHOD OF MANUFACTURING THE SAME” filed on Oct.26, 2001, both of which are incorporated in this application as if fullyset forth herein. The LED 54 is partially fabricated on a sapphiresubstrate that is subsequently removed. Removal of sapphire substratemay be done by, for example, laser lift-off. As shown, the LED 54includes a GaN buffer layer 55 having an n-metal contact 56 on a bottomsurface and a relatively thick n-GaN layer 58 on the other. The n-metalcontact 56 is beneficially formed from a high reflective layer that isoverlaid by a high conductivity metal (beneficially Au) to form an ncontact pad 57. An active layer 60 having a multiple quantum well isformed on the n-type GaN layer 58, and a p-GaN layer 62 is formed on theactive layer 60. A transparent conductive layer 64 is then formed on thep-GaN layer 62, and a p-type electrode 66 is formed on the transparentconductive layer 64. A p contact pad 68 is then formed on the p-typeelectrode 66.

The vertical GaN-based LED 54 has advantages in that step etching is notrequired. However, to locate the n-metal contact 56 below the GaN bufferlayer 55, the sapphire substrate (not shown) that is used for initialGaN growth is removed. Sapphire substrate removal using laser lift-offis known, reference U.S. Pat. No. 6,071,795 to Cheung et al., entitled,“Separation of Thin Films From Transparent Substrates By SelectiveOptical Processing,” issued on Jun. 6, 2000, and Kelly et al. “Opticalprocess for liftoff of group III-nitride films”, Physica Status Solidi(a) vol. 159, 1997, pp. R3-R4). Furthermore, highly advantageous methodsof fabricating GaN semiconductor layers on sapphire (or other insulatingand/or hard) substrates are taught in U.S. patent application Ser. No.10/118,317 entitled “A Method of Fabricating Vertical Devices Using aMetal Support Film” and filed on Apr. 9, 2002 by Myung Cheol Yoo, and inU.S. patent application Ser. No. 10/118,316 entitled “Method ofFabricating Vertical Structure” and filed on Apr. 9, 2002 by Lee et al.Additionally, a method of etching GaN and sapphire (and other materials)is taught in U.S. patent application Ser. No. 10/118,318 entitled “AMethod to Improve Light Output of GaN-Based Light Emitting Diodes” andfiled on Apr. 9, 2002 by Yeom et al., all of which are herebyincorporated by reference as if fully set forth herein.

In principle, the vertical GaN-based LED 54 is preferred. Reasons forthis include the fact that a 2″ diameter sapphire wafer has thepotential to produce about 35,000 vertical GaN-based LEDs, but onlyabout 12,000 lateral GaN-based LEDs. Furthermore, the lateral topologyis more vulnerable to static electricity, primarily because the twoelectrodes/pads (44/46 and 48/50) are close together. Additionally, asthe lateral topology is fabricated on an insulating substrate, and asthe vertical topology can be attached to a heat sink, the lateraltopology has relatively poor thermal dissipation.

While the vertical GaN-based LED 54 will be preferred in manyapplications, at the present time, lateral topology blue LED chips 30are more common. Furthermore, the principles of the present inventionare fully applicable to both types of blue LEDs (as well as with hybridsand variations). Therefore, without implying any loss of generality, thesubsequent description of the fabrication of single-element white LEDswill make specific reference to the use of a lateral blue-LED chip 30.

Referring now to FIG. 4, a passivation layer 80 is formed over the blueLED chip 30. A suitable passivation layer 80 may be an SiO₂ orSi_(x)N_(y) layer of 1000 Å-thick, for example, formed on exposedsurfaces of the LED chip 30 using PECVD. Alternatively, the passivationlayer 80 may be formed by sputtering, electron beam evaporation, or bycoating with a suitable protective material, such as epoxy or flowableSiO₂. Note that spin-coating is a particularly useful coating technique.However, PECVD is beneficial because it can form the passivation layer80 on the sidewalls of the blue LED chip 30.

Referring now to FIG. 5, the passivation layer 80 is then patterned toexpose the p and n contact pads 46 and 50 using a suitable etchant. Forexample, BOE, HF, and/or photo-resist stripping can be used to exposethe pads.

Then, as shown in FIG. 6, a thin film layer 86 of, for example, afluorescent material (such as phosphor or a tin-containing compound) isformed on the passivation layer 80 so as to cover the blue LED element.Other suitable materials can be used for the thin film layer 86 toconvert a light of first wavelength (a first color) to a light of secondwavelength (a second color). Here, if a blue LED is used and coated witha phosphor thin film, for example, in accordance with the presentinvention, the blue light would be converted to white light by thephosphor, thus producing an “on-chip” white LED. Using different colorLEDs and different color influencing materials would result in differentcolors produced directly from the chip.

The thin film layer is beneficially formed using metal organic chemicalvapor deposition (MOCVD), atomic layer chemical vapor deposition (ALD),plasma enhanced MOCVD, plasma enhanced ALD, photo enhanced CVD, or otherchemical vapor deposition methods. Preferably, the thin film layer 86 isabout 10 μm or so thick. Thus, the thin film layer 86 is an integralelement of the chip, and not part of a package. Regarding the filmthickness, in general the thinner the better. The thickness can bereduced by growing dense thin film layers.

Referring now to FIG. 7, the thin film layer 86 is patterned to exposethe p and n contact pads 46 and 50 using a suitable solvent (which willdepend on the composition of the thin film layer 86). Bonding wires 90and 92 are then bonded to the p and n contact pads 46 and 50,respectively.

Referring now to FIG. 8, an optional second passivation layer 94 (whichis optically transparent) is then formed over the structure of FIG. 7.Beneficially the first and second passivation layers 80 and 94 areformed using the same process. The result is a white LED 100.

The white LED 100 can then be encapsulated into a package, such as alamp package or a surface mount package. However, the white LED 100 alsocan be used unpackaged and/or as part of another assembly.

In some applications it will be beneficial to incorporate a reflectorbetween a contact pad and an adjacent semiconductor layer. For example,as shown in FIG. 9, if a vertical LED 54 is used as the blue lightsource for a white LED 101, it might be advantageous to incorporate areflective layer 104 between the n-metal contact 56 and the n contactpad 57. In that case, it is advantageous to include the secondpassivation layer 94 under the n contact pad 57 after the bonding wire92 is attached. Likewise, the second passivation layer 94 isbeneficially over the p contact pad 68. However, is should be understoodthat in all cases the second passivation layer 94 is optional.

The foregoing embodiments have described new, useful, and nonobviouswhite LEDs 101. However, the general principles of depositing thin filmsthat change the color of input light, such as by a thin film material,are applicable to more than just white LEDs. It is entirely possible toimplement LEDs that emit other then white light by depositing variousthin film materials on LEDs that emit light of different colors.Therefore, while the embodiments and examples set forth herein arepresented to best explain the present invention and its practicalapplication and to thereby enable those skilled in the art to make andutilize the invention, others who are skilled in the art will recognizethat the foregoing description and examples have been presented for thepurpose of illustration and example only.

1. A light emitting device, comprising: an LED chip that emits lighthaving a first wavelength, wherein the LED chip includes a firstelectrical contact and a second electrical contact; a thin film layerformed over the LED chip, wherein the thin film layer interacts with thelight to form light having a second wavelength, and wherein the thinfilm layer has an opening corresponding to the first electrical contact.2. The device according to claim 1, wherein the thin film layercomprises at least one of a fluorescent material, a tin-containingmaterial, and a phosphor.
 3. The device according to claim 1, furthercomprising a passivation layer between the LED chip and the thin filmlayer.
 4. The device according to claim 3, wherein the passivation layercomprises at least one of Si, polymers, oxides and nitrides.
 5. Thedevice according to claim 3, further comprising a second passivationlayer over the thin film layer.
 6. The device according to claim 3,wherein the passivation layer is disposed over at least one of a sidesurface and a top surface of the LED chip.
 7. The device according toclaim 1, wherein the thickness of the thin film layer is about 10 μm. 8.The device according to claim 1, wherein the thin film layer is anintegral element of the LED chip.
 9. A light emitting device comprising:an LED chip including a semiconductor structure having multi-layers thatemits light having a first wavelength, wherein the LED chip includes afirst electrical contact and a second electrical contact respectivelylocated at opposite sides of the semiconductor structure; a passivationlayer formed over the LED chip; and a thin film layer over thepassivation layer, wherein the thin film layer interacts with the lightto form light having a second wavelength, and wherein at least a portionof the passivation layer is in contact with the thin film layer.
 10. Thedevice according to claim 9, wherein the LED chip is attached to a heatsink.
 11. The device according to claim 9, wherein the thin film layeris formed over the LED chip, and wherein the thickness of the thin filmlayer is substantially uniform.
 12. The device according to claim 9,wherein the thin film layer comprises at least one of a fluorescentmaterial, a tin-containing material, and a phosphor.
 13. The deviceaccording to claim 9, wherein the thickness of the passivation layer isabout 1000 Å.
 14. The device according to claim 9, further comprising areflective layer over the semiconductor structure.
 15. The deviceaccording to claim 1, wherein the opening in the thin film layer exposesa top surface of the LED chip.
 16. The device according to claim 1,wherein the thickness of the thin film layer is substantially uniformover at least a portion of a top surface of the LED chip, a side surfaceof the LED chip, a side of the first electrical contact or a side of thesecond electrical contact.
 17. The device according to claim 16, whereinthe thin film layer is configured to enhance the uniformity of the lighthaving a second wavelength.
 18. The device according to claim 1, whereinthe thickness of the thin film layer is substantially uniform over atleast a portion of a top surface of the LED chip.
 19. The deviceaccording to claim 1, wherein the opening is configured to prevent thethin film layer from contacting a bonding wire bonded to the firstelectrical contact.
 20. The device according to claim 1, wherein theopening prevents the thin film layer from coming into contacting withthe first electrical contact.
 21. The device according to claim 1,wherein the thin film layer is configured to expose the first electricalcontact.
 22. The device according to claim 1, wherein the thin filmlayer has a second opening corresponding to the second electricalcontact.
 23. The device according to claim 22 further comprises apassivation layer between the LED chip and the thin film layer, thepassivation layer having a first opening and a second opening, the firstopening in the passivation layer corresponding to the first opening inthe thin film layer and the second opening in the passivation layercorresponding to the second opening in the thin film layer, wherein thefirst and the second openings in the thin film layer and the passivationlayer expose at least a portion of the first electrical contact and thesecond electrical contact, respectively.
 24. The device according toclaim 3, wherein the passivation layer comprises an openingcorresponding to the opening in the thin film layer.
 25. The deviceaccording to claim 3, wherein the opening in the passivation layer andthe opening in the thin film layer expose the first electrical contact.26. The device according to claim 3, wherein the passivation layer isconfigured to prevent the thin film layer from coming into contact withthe first electrical contact.
 27. The device according to claim 3,wherein at least a portion of the passivation layer prevents the thinfilm layer from coming into contact with the LED chip.
 28. The deviceaccording to claim 3, wherein the passivation layer is disposed on aside surface of the LED chip and extends to at least a portion of a topsurface of the LED chip.
 29. The device according to claim 9, whereinthe passivation layer comprises at least one of Si, polymers, oxides andnitrides.
 30. The device according to claim 9, further comprising asecond passivation layer over the thin film layer.
 31. The deviceaccording to claim 9, wherein the passivation layer is configured toexpose at least one of the first and the second electrical contacts. 32.The device according to claim 9, wherein the passivation layer preventsthe thin film layer from coming into contact with at least one of thefirst and the second electrical contacts.
 33. The device according toclaim 9, wherein at least a portion of the passivation layer preventsthe thin film layer from coming into contact with the LED chip.
 34. Thedevice according to claim 9, wherein the passivation layer is disposedover at least one of a side surface and a top surface of the LED chip.35. The device according to claim 9, wherein the passivation layer isdisposed on a side surface of the LED chip and extends to at least aportion of a top surface of the LED chip.
 36. The device according toclaim 11, wherein the thin film layer is configured to enhance theuniformity of the light having a second wavelength.
 37. A light emittingdevice comprising: an LED chip that emits light having a firstwavelength, wherein the LED chip includes a first electrical contact anda second electrical contact; a passivation layer over the LED chip, thepassivation layer having at least one first opening; and a thin filmlayer formed over the passivation layer, the thin film layer having atleast one second opening corresponding to the first opening, wherein thethin film layer interacts with the light to form light having a secondwavelength, and wherein one of the electrical contacts is aligned withthe first and second openings.